The present invention relates generally to electrical connectors and methods, and more particularly to an integrated circuit socket and method for altering the effective pinout arrangement and/or connections of an integrated circuit.
In the modern electronic industry, integrated circuits and similar mechanically configured devices frequently are used. Such devices may, for example, be a microprocessor, a read only memory (ROM), a random access memory (RAM), logic arrays, integrated logic circuits, switches, hard disk drive (HDD), etc. Such devices are usually mechanically configured to have a three-dimensional rectangular package within which the active or passive circuitry components, switches, etc., are contained and a plurality of electrical leads extending outwardly from the package to provide electrical connections for the respective circuits within the package to circuitry external to the package. For convenience of description, each of such devices will be referred to hereinafter as an integrated circuit (IC) device; however, such label is intended to include the previously listed devices and other types of devices that are contained in a packaged configuration. Moreover, such electrical leads sometimes are referred to as terminals, contacts, pins, etc., and for convenience of the following description, the same will be referred to as pins.
Electronic circuitry is usually designed for use with a particular integrated circuit, such as a specific microprocessor manufactured by a specific manufacturer or a specific circuitry such as a preamp for a HDD and having a specific pinout pattern or configuration. These pins are numbered for sake of identification. For example, pin number 1 of the integrated circuit package may be intended to connect to a voltage source, pin number 2 may be an interrupt input for the microprocessor, pin number 3 may be a ground connection, etc. The layout and interconnections of printed circuit traces on a printed circuit board to connect to the IC intended to use a specific microprocessor usually are designed for use with a particular microprocessor of a particular manufacturer.
In addition, such integrated circuits are used in conjunction with magnetic disk drives. These magnetic disk drives have read/write heads which are used for both writing data to a magnetic disk and reading data from the magnetic disk. During a write operation, a write signal is provided to a selected read/write head from a write control circuit. The write signal represents data to be encoded onto the magnetic disk. More particularly, the read/write head receives encoded digital data from a xe2x80x9cchannelxe2x80x9d chip. The transitions of the signal received from the channel chip cause the write current flowing within the read/write head to reverse direction , which in turn induces a flux reversal in the magnetized material of the medium. During a read operation, the read/write head senses flux reversals from the magnetic disk and amplifies the signal for the channel by a preamplifier. The flux reversals are encoded onto the magnetic disk during the write operation. Based on the flux reversals, the read/write head provides a read signal to a read channel. The read circuit amplifies the read signal, and the channel circuit recovers the data. The read circuit then provides the data to a magnetic disk controller for further processing.
Each magnetic disk in the disk drive has a corresponding xe2x80x9cheadxe2x80x9d adjacent to the top and bottom surfaces of the disk. Thus, there are two N heads per stack where N equals the number of disks in the drive. Normally, only one head is active at any time. Thus, for each head, there may be a plurality of connectors for either providing a read or write function. For example, one head may require four connections, namely a ground wire, a read wire, and a pair of write wires.
In U.S. Pat. No. 4,609,241 a socket where the IC is placed can be readily programmed to adapt the pinout configuration of the integrated circuit device for convenient plug-in use for substitution in an environment such as the socket. However, such a device leaves the pinout configuration of the integrated circuit unchanged.
These heads require at least two current paths so that current can flow in two directions in the head. Thus, a 0 or 1 can be written on the magnetic disk. To write current in one direction, two terminals are required, and thus, for each head, four terminals are required for current to flow in two directions. It is possible to reduce the number of connections for the pins by using a common ground connection. Conventional ICs are limited by having a fixed pinout configuration. A fixed pin configuration is not desirable. Different manufacturers require the same functions in an IC, but different pinout configuration results in a multitude of parts having to be produced in order to satisfy manufacturer pinout configurations.
In accordance with the present invention, a programmable IC is described to change the pinout configuration from a first pinout configuration to a second pinout configuration. Thus, the same integrated circuit can be used for different manufacturers having different pinout configurations.